<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
</body>
</html>
<script>
    var days = prompt('请输入一个天数')
    var zr = days % 7
    if(zr == 0){
        alert("星期二")
    }
    if(zr == 1){
        alert("星期三")
    }
    if(zr == 2){
        alert("星期四")
    }
    if(zr == 3){
        alert("星期五")
    }
    if(zr == 4){
        alert("星期六")
    }
    if(zr == 5){
        alert("星期日")
    }
    if(zr == 6){
        alert("星期一")
    }
</script>
